Regenerative furnace.



A. L. STEVENS. REGENERATIVE FURNACE.

APPLICATION FILED MAY 19. 1916- Patented Jan. 21, 1919.

4 SHEETS-SHEET I.

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A.-L. STEVENS.

REGENERATIVE FURNACE.

APPLICATION FILED MAY 19. I916.

1 ,292,1 26, Patented Jan. 21, 1919.

4 SHEETS-SHEET 2.

A. L. STEVENS.

REGENERATIVE FURNACE.

APPLICATIQN FILED MAY 19, 1916.

Patented Jan. 21, 1919.

INVENTOI? ATTORNEY J A. L. STEVENS.

REGENERATIVE FURNACE. APPLICATION FILED Ill/\Y I9. I916- jl,292,126. Patented Jan. 21,1919

F'ra/ fan.

INVENTOR 7 fdmzhz,

A TTORIVEI- nnrrnn .iifiCtTl-IUR L. STEVENS, OF CHICAGO, ILLINOIS.

nneurinnnrrvn FURNACE.

Specification of Letters Patent.

Patented Jan. 21,1919.

Application filed Key 19, 1916. Serial No. 98,499.

To all whom may con:

Be it known that 1. .JU-E'FHUR L, S'mvims,

acitizen of the United States, residing at Chicago, in the couiny of Cook and State of IlllIlOlS, have invented certain new and useful Improvements in Regenerative Furnaces, of which the following a specification.

My invention relates to regenerative furnaces, and more particularly to apparatus of the forging furnacetypc in which there is a Working opening leading); to the heating chamber which is open constantly during the operation of the furnace, or at least for most of'the time.

One of the principal objects of the invention is to provide a furnace of this general type in which a iintively high temperature may be mai ined; in which the tem erature will be lllllLUl'lll throughout the W01 .ing chamber; and in which, although there may be a. constantly open working opening, excessive air in the beating chamber will be prevented so that the flame will be a neutipl or even a reducing flame.

A further object is to provide'a furnace in which it is pos'sible'to economically use a lean, cold producer which has been cleaned to remove the soot and tarry matters which, incidentally, n'iay be saved. By using a clean gas the maintenance cost is reduced.

A further objcci is to provide an economical and ellicient furnace which can be operated without any stark draft and in which the fuel will l ic;co1nplclel v burned so that there will be no discharge of noxious gases into the room in which the furnace is located.

A' further object is to provide a furnace for generating relatively high temperatures, in which the heat developed ill be utilized. to the fullest extent; that is, a furnace C()Il structcd so that the gases issuing from the discharge openings will be at a very low temperature compari-rd with the temperature of the heating chamber;

ll'ly invention consists iif'l'l'ic novel coir.

structions. arrangements and devices to be hereinafter described and claiu'ied. for can ryiug out the above stated objects and such other objects as will'be mentioned in the following spccificati'c". A

The invention cons further in 'a novel and improved method of proi'lucing and maintaininghi. high:temperature inj an in closed, or substantially'inclosed, s 'iace by means of a neutral or reducing flame. I desire herein to claim this method as such.

The invention is illustrateclin the accompanying drawings as cmbodiedin a forging furnace of preferred constri'lction.

Figure 1 shows the furnace in front elevation.

a. plane parallel to the front of the furnace.

Fig. 3 a sectioualview on line of Fig. 2.

Fig. l; is a. vertical section and Fig. 5 a sectional plan of one of a pair of preferably identically constructed valves for controlling the supply of gas to the flow of air tl'irough the furnace.

Fig. (3 is a plan view of the furnace.

Fig. 7 is an enlarged sectional view on line 7--7 of Fig. 1. i

Fig. 8 is a view, in the exhaust valves, an

Fig. 9 is a diagrammatic vertical sectional view to illustrate the flow of the gases through the supply pipes, fines, working chamber and rcgenerators. I

Like characters of reference indicate like parts in the several figures of the drawings.

I shall describe the preferred construction shown in the drawings'but with the understandin that while iif'matters of detail this particu ar embodiment of the invention involves some points of novelty, considering Xerspective, of oneof the invention more broadly, the principles thereof might be employed, without departure from the scope and objects of the invention as defined in the claims, in a furnace quite different in its design and mecl'ianical construction.

Referring to Figs. 1 to 8 inclusive, the numerals 10 designate corner angle pieces which terminate in legs 11. 12 is a front plate, 13. 13 side platcs..and 14 a back piste, all of metal and secured to said corner angle pieces. 15 is a top plate supported on angle bars l6, 16, secured to the front and back plate, respectively. Extenrding alon the top of the side plates are angle bars 1 and along their bottom edges angle bars 18. The latter support a number of transversely arranged T-irons '19 that carry the brickwork of the furnace, a stratum of heatinsulating material, for example, cork brick 320 being interposedbetween the T-irons "and thelower courses ofthe bricks. The

heating chambers 21'- 1 extendsfrom-"thew Fig. 2 is a vertical cross sectional view in Laeatec front to the back of the furnace and is reached through a working opening 22 in the brickwork 23 ofthe front wall of the furnace. The effective size of the working opening is varied by means of a fire brick element 24: which is supported in a casting Z5 slotted at 26 so that it may be bolted at different elevations to projecting webs 27 on the front corner pieces 10. The casting is formed with a water chamber 28.. 29, 29 are the waterpipes which lead to and from the water chamber. The lower portions 30 of the brick side walls are thicker than the upper portions 31 and, are formed with horizontal fines 32*, 32" leading into the heating chamber, these fines conuuunicating by vertical fines 33, 33 with the regcnerators A and B, respectively. A plurality of gas burners til -34" extend into the lines 32*,32". 35 is a gas supply pipe having branches 36 leading to the burners. A valve 37 directs the gas either to one side of the furnace or the other. as may be desired. A brickwork arch 38 forms the top of the heating chamber. The hearth is formed by lwickwork 39. Above and spaced from the. arch 38 is a sec-- ond arch it) which supports the checker work of the regenerators A. B, and the dividing wall 41 between the regenerators.

By the arrangements just described such portions of the brickwork of the hearth may be removed and new bricks put in by removing the supporting T-irons 19. Furthermore, when it is necessary to replace the bricks in the arch 38 this arch may be torn out without disturbing the checker-work of the regencrators which is supported by the upper arch 40. i

The top walls of the regenerators are pierced by a series of relatively large dis charge openings i2, 42" which lead directiy to the-atmosphere. These discharge openings are designed to be covered by slide valves 48 which more on a damper plate l-l slidably mounted on the top plate 15 of the furnace. The damper plate has openings 45 and is formed with lugs 46 with threaded perforations to receive set screws -l-7whieh are carried by a flang it on the top pllate 15. The damper plate may be adjusted by the set screws, which are locked by nuts 49. so as to vary the position of the openings 45 with respect. to openings 4'2. whereby the discharge of gases from the regenerators may be regulated. The. valves are formed with forks 50 which aroen a 'ed by a rod 51 connected by links 52 to levers 53 rigidly counocted with a rock shaft 54 mounted in bracketsbi) on one of the side plates of the furnace. Theroek shaft is operated by a lever 56. 57, 58 are spacing sleeves surrounding the shaft 51.

59 is the air supply pipe. connected with a fan or other suitable air compressor (not shown). The air from pipe 59 is directed by i a this construction being iliustratedin h igs. 4t

and The casing of the valve (valve 60 being the one shown and described}; is formed with a neck 63 connected with the air supply pipe 59 and with ports 65, 65 communicating with the branch pipes 61. In the ports (35 are arranged spiders 66 Slid ably supporting the valve body '67 which is provided at opposite ends with "studs 68 passing through central. openings in the spiders, the valve body 6? being provided. with two valves 69 and. the rims 7'0 of the spiders forming seats for the valves. The valve body is slotted at '71 to receive the rounded end of a finger 72 which is rigidly secured to a shaft 73. This same shaft carries on its lower end a finger corresponding 1 to the finger 7'2 which operates the valve body of valve 37. The shaftl 73 carries an arm Tl connected by a link with an arm 76 on the shaft St, the arm (76 being preferably formed with a slot W, the end of link 75 being in the form of a hook 78- which passes through slot 77. i i

By means of these arrangements tliefuel and air supply valves and the discharge valves are operated simultaneously by a single movement of lever 56.

in. order to a tend the hearth 39 a triflebeyond the working openingan angular casting 79 is bolted to webs 80 on the front corner pieces .10 of the furnace. The outer courses of the hearth bricks are supported by casting 79.

Operation: In the drawings the turna e is shown as being supplied with fuel and. air from the side of regencrator A and exhausting through regenerator B. The gas enters the horizontal ducts??? through the gas burners 2-H. Here it meets streams of heated air which are conducted from'regenerator A through the vertical tines Thefresh air isupplied to the rt-generator A through branch pipes 61, 623*, under coir trollable prussrn'r. The products of combustion pass into the regenerate! B through which the furnace is shown as exhausting.

In a furnace of this type-it is necessary, be

vent on the one hand cause of the character of the work performed, to have an opening-into the heating chamber which is open constantly during the operation of the furnace. Inorder to pre air from being drawn into the heating chamber through the working opening or, on the other hand, the. flames from escaping therethrough to an undesirable. extent-the aggregate area of the discharge ports 42 is calculated with reference to the temperature desired to maintain a pressure in the heating chaiiilier just a trifle above that of the atmosphere. For a furnace intended for one service this will be taken care of in the design of the furnace. 'here the furnace is intended for the pro duction of different temperatures the outlet ports will be provided with the adjusting damper hereinmshown and described. by meansof which the size of the ports may be varied as required The result is that no appreciable amount of air enters the heating chamber through the working opening. This is important in order to prevent oxidation of the metal operated upon and to insure against unequal heating of different parts of the chamber. In other words, successful operation depends upon a proper balance of pressures whereby the desired high temperature is maintained in the heating chamber, although constantly open to the atmosphere, and whereby the burned gases are dischargedatallow temperature so that fuel is economized. By such operation a neutral or possiblya reducing flame is produced in the heating chamber at a minimum fuel cost, which heats the chamber uniformly throughout. This balance of pros sures is made possible by arranging the regenerators above the heating chamber, by makin the exhaust openings from the regenerators large and adjustable when the furnace is designed for different services, and by depending upon the regenerator through which the burned gases are. escaping to act as a stack; a stack. literallyspeaking..being entirely superfluous so far asthe operation of the furnace isconcerned. The a'r and fuel gas pressures will be so regulated as to supply enough fuel and oxygen to raise the tcmpe'ature in the heating chamber to the desired point.

By introducing the air and gas 'into the furnace at intervals along one side of the same and by dividing the fuel, and the air also, into separate currents or jets, the gas from each jet mingling with a definite, confined stream of'air, a homogeneousmixture of air and gas is produced which insures a uniform and high temperature by preventing of'gases through the furnace; the fuel gas,

Fahrenheit, even when ployed it is possible to use,

gas, will develop high principle to the small furnace,

to obtain very high temperatures at.

may be discharged directly into the room,

where the furnace is located, eliminating the necessity of a stack. As another element of economy, the furnace may be operated so as to deliver the discharge gases at a relatively low temperature, say four hundred degrees the temperature in the furnaceis as high as the temperature mentioned. This means a utilization of the heat to the fullest extent and makes it possible to cheapen very considerably the cone.

valves for controlling the It is not necessary to preheat the gas. There is no provision for assing 'the gas through regenerators. his simplifies and cheapens the construction of the furnace and makes it. much more compact than would otherwise be the case..- By reason of the fact that cold gas may be, em-

economically, a gas'which has been cleaned to remove soot, and tarry matters. This reduces the cost of up-keep of the furnace. and makes it feasible to save the tarry matters in the gas which are valuable by-products. Cold gas can be handled more cheaply than hot gas because, being smaller in volume, the pipes and valves through which it passes from the producer to the furnace may be made smaller. The use of cold gas also eliminates the water cooling of the valves and ducts.

\Vhile large! furnaces might be designed according to my invention, I have particularly in mind toprovide a fuel burning furnace, of the regenerati've type which might be made comparatively small, for use in heating steel for forging purposes, which, in

struction of the exhaust ports.

fpite of its small size and the employment of an inexpensn'e fuel, such as lean producer temperatures. Small furnaces, as heretofore designed. have. not. been capable of developing high temperatures when cheap fuel, such as producer gas, is used. My invention hasreshlted in the successful application of the regenerative possible small construction, upkeep and fuel cost,

and withoutdanger-of oxidizing the metal Operatedupon, I. I claim:

i l "l, i-'r NJ. as, 1. In a furnace, the combination of regencheap.:

entering the regenerator and operated as making it lever, and connections between said rod and operating lever.

Q. In a furnace, the combination with an air supply pipe having branches leading to oppr te sides of the furnace, a fuel supply pipe having branches leading to opposite sides of the furnace, valves in each of said pipes, arranged one above the other, and

ada ted, in each case, to direct the fluid *therein to one of the branch pipes, a. shaft provided with fingers for operating said valves simultaneously, and means for giving a movement of partial rotation to said shaft.

3. A furnace comprising a heating cham-- her having a constantly open working orifice, regcnerators through which air is introduced into the heating chamber and products of combustion discharged therefrom respectively, in alternation, said regenerators being provided with discharge openings and valves to close the same, means for introduc; ing air under pressure into one of said regenerators at a time and means for varying the effective crossisectional area of the discharge openingof the regenerator through which the products of combustion are dis charged; I

4. In a furnace, the combination of regenerators having-discharge openings in the top, valves slidably arranged so as to be 'movable from positions closing the opening in one regenerator to positions closing the opening in the other regenerator, means for operating said valves, and av damper plate to vary the effective areas of said discharge openings.

5. A furnace comprising a heating chamher having a constantly open working orifice, regenerators arranged above said heat ing chamber through'which air is intro duced into the heating chamber and products of combustion discharged therefrom respectively, in alternation, said regenerators being provided with discharge openings at their upper ends and valves to close the same, means for introducing air under pressure into one of said regencrators at a time and means for varying the ell'ective cross sectional area of the discharge opening of the regencrator through which the products of combustion are discharged.

6. Ina regenerative furnace, the combina tion of a heating chamber, a pair of re generators arranged above said chamber through which in alternation air is intro duced into and burned gases are discharged from the heating chamber, means for introducing fuel gas into the chamber, means for forcingair into the chamber through said regenerators alternately; said chamber hav-. mg a working orifice constantly open to the atmosphere and the regenerators provided at the top with discharge openi'ngsifor burnt gases; and means for varying the effective size of said discharge openings in accordance with the temperature maintained in said heating chamber whereby a pressure is maintained in the chamber. preventingappreciable inflow of air through thy-working peratul'e" in a chamber having an orifice con-' stantly open to the atmosphereand utilizing the heat of the burnt gases, which consists in introducing air into said chamber and discharging the: burnt gases therefrom through heat stoning passageways providing 1 air and gas columns which are above the chamber so'that the heavier air column overbalances the lighter column of gas, and

controlling the discharge of burnt gases in accordance with the temperature in the heat-.

ing chamber so as to maintain a pressure in said chamber which will preventappr'eciable inflow of aiitthrough said orifice without causing substantial discharge of products of combustion therefrom.

9. Method of maintaining high temperature in a chamber having an orifice constantly open to the atmosphere ndiutilim ing thcheat ofthe burnt gases hich consists in introducing air into" n chamber and discharging the burnt,gases therefrom through heat storing passageways providing air and gas columns which are above the chamber so that the heavier air column balances the lightercolumn of gas; mixing fuel gas, without pre heating,with the ini flowing air in the for m of a plurality of streams at the place where the air: passes from the heat storing passageway into the heating chamber and controlling the (llS- charge of burnt gases in .accordance with the temperature in the heating chamber so as to maintain a prcssuro in said heating chamber which \Vlll prevent appreciable inflow of air through said orifice without causchamber, a support for the same, a pair of regeneratorsarranged above the heating chamber having discharge openings in the mg substantial discharge of the products of i each of the aforesaid flues, an air supply main above the regenerators having branches for introducing air into the up er ends of the regenerators, respectively, va ves in said air and gas mains, valves whereby said discharge ogenings in the regenerators may be opene and closed, and apparatus for operating said valveslso air may be introduced into the chamber through first one regenerator and then the other and mixed with gas introduced into the furnace from the same side, while the productsof com- 7 bustion are discharged through the other regenerator in each case.

11. In a regenerative furnace, the coin bination of means constituting a heating chamber, a support for the same, a air of regenerators arranged above the eating chamber having discharge openings in the top for the products of combustion and fines connnunicating with opposite sides of the heating chamber, respectively, a gas main arranged under the heating chamber having a plurality of branch pipes leading to each of the aforesaid fines, an air supply mainabove the regenerators having branches for introducing air into the upper ends of the regenerators, respectively, valves in said air and gas mains, valves w ereby said discharge openings in the regenerators may be opened and closed, apparatus for operating said values so air may be introduced into the chamber through first one 'regenerator and then the other and mixed with gas introduced into the furnace' from the same side While the products of combustion are discharged through the other regenerator in each case, and means for varying the effective size of the discharge openings in the regenerators, for the ur )ose' described.

- ARTHfTR 'L. STEVENS. 

